Fuel management systems having a fluororubber component in contact with biodiesel fuel

ABSTRACT

Disclosed herein is a fuel management system having at least one fluororubber component in contact with biodiesel fuel wherein said 5 fluororubber component comprises i) a peroxide cured fluoroelastomer comprising copolymerized units of vinylidene fluoride and at least one other fluoromonomer, said fluoroelastomer having cure sites selected from the group consisting of iodine and bromine atoms, and ii) 0 to 5000 parts by weight of an inorganic acid acceptor per million parts fluoroelastomer.

FIELD OF THE INVENTION

This invention relates to fuel management systems having fluororubbercomponents in contact with biodiesel fuel wherein said fluororubbercomponent comprises i) a peroxide cured fluoroelastomer comprisingcopolymerized units of vinylidene fluoride and at least one otherfluoromonomer, said fluoroelastomer having cure sites selected from thegroup consisting of iodine and bromine atoms, and ii) 0 to 5000 parts byweight of an inorganic acid acceptor per million parts fluoroelastomer.

BACKGROUND OF THE INVENTION

Fluoroelastomers having excellent heat resistance, oil resistance, andchemical resistance have been used widely for sealing materials,containers and hoses. Examples of fluoroelastomers include copolymerscomprising units of vinylidene fluoride (VF₂) and units of at least oneother copolymerizable fluorine-containing monomer such ashexafluoropropylene (HFP), tetrafluoroethylene (TFE),chlorotrifluoroethylene (CTFE), vinyl fluoride (VF), and a fluorovinylether such as a perfluoro(alkyl vinyl ether) (PAVE). Specific examplesof PAVE include perfluoro(methyl vinyl ether), perfluoro(ethyl vinylether) and perfluoro(propyl vinyl ether). Other examples offluoroelastomers include the copolymers of tetrafluoroethylene with aperfluoro(alkyl vinyl ether) such as perfluoro(methyl vinyl ether)(PMVE).

In order to develop the physical properties necessary for most end useapplications, fluoroelastomers must be crosslinked. A preferred curingsystem for many end uses is the combination of an organic peroxide and amultifunctional unsaturated coagent. The coagent forms crosslinks byreacting with bromine or iodine atom cure sites on the fluoroelastomerpolymer chain. A preferred cure site is an iodine atom bonded to acarbon atom on the fluoroelastomer chain.

Typical peroxide curable fluoroelastomer compositions contain 1 to 10parts by weight of an inorganic acid acceptor per hundred parts byweight fluoroelastomer. Inorganic acid acceptors include metal oxides,metal hydroxides and hydrotalcite compounds. The function of inorganicacid acceptors in a peroxide curable fluoroelastomer compound is toneutralize acids that are byproducts of the curing process.

However, peroxide cured fluoroelastomer articles containing inorganicacid acceptors generally exhibit unacceptably high volume swell, thatmay lead to seal failure, when seals are exposed to biodiesel fuel forlong periods of time or at elevated temperatures, especially when thefuel contains a minor amount of water. Biodiesel fuels often containwater as an impurity. The source of the water may be a washing step inthe fuel manufacturing process or exposure to moist air during storage.Typical specifications for manufactured biodiesel allow for some waterimpurity, e.g. ASTM D6751.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a fuel management systemhaving at least one fluororubber component in contact with biodieselwherein said fluororubber component has excellent (i.e. low) volumeswell in biodiesel fuel. Said fluororubber component comprises i) aperoxide cured fluoroelastomer comprising copolymerized units ofvinylidene fluoride and at least one other fluoromonomer, saidfluoroelastomer having cure sites selected from the group consisting ofiodine and bromine atoms, and ii) 0 to 5000 parts by weight of aninorganic acid acceptor per million parts fluoroelastomer.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to fuel management systems having atleast one fluororubber component in contact with biodiesel fuel. Thefluororubber component comprises a peroxide cured fluoroelastomercomposition and is substantially free of inorganic acid acceptors. By“substantially free” is meant 0 to 5000 (preferably 0 to 1000, morepreferably 0 to 500, most preferably 0) parts by weight of an inorganicacid acceptor per million parts by weight fluoroelastomer. Suchfluororubber components have surprisingly low volume swell when exposedto biodiesel fuel for long periods of time and/or at elevatedtemperatures.

By the term “fuel management system” is meant equipment employed in themanufacture, storage, transportation and supply, metering and control ofbiodiesel fuel. Fuel management systems include those contained inbiodiesel manufacturing plants, motor vehicles (e.g. trucks, cars,boats), stationary diesel powered devices (e.g. electrical generators,portable pumping stations) and those associated with biodiesel fueltransportation, storage and dispensing. Specific elements of fuelmanagement systems include, but are not limited to fuel tanks, fillerneck hoses, fuel tank cap seals, fuel line hoses and tubing, valves,diaphragms and fuel injector components, o-rings, seals and gaskets. Anyor all of these elements may comprise one or more fluororubber componentthat contacts biodiesel fuel.

By “biodiesel fuel” is meant a fuel suitable for use in a compressionignition (diesel) engine compromising one or more fatty acid alkylesters (FAAE) of biological origin (i.e. derived from animals orplants). These FAAEs are typically methyl or ethyl esters of fatty acidsderived from vegetable oils or animal fats. Specific examples includerape seed oil methyl ester (RME), soybean oil methyl ester (SME), palmkernel oil methyl ester (PME) and the like. Also included are blends ofthese FAAE based materials with conventional petroleum based dieselfuel. Petroleum diesel/biodiesel blends are conventionally denoted asBxx fuels where “xx” is the volume percent of the FME based biodiesel inthe blend. For example, B100 denotes a biodiesel fuel containing nodeliberately added petroleum component. B20 denotes biodiesel fuelcontaining 20 vol. % of a B100 fuel and 80 vol. % of petroleum dieselfuel.

By “inorganic acid acceptor” is meant metal oxides, metal hydroxides andhydrotalcite compounds, e.g. CaO, Ca(OH)₂, MgO, ZnO, etc.

Fluororubber components of this invention include, but are not limitedto seals, gaskets, o-rings, tubing, the fuel contact layer of multilayerhoses, valve packings, diaphragms, and tank liners.

The fluoroelastomers employed in this invention comprise copolymerizedunits of vinylidene fluoride (VF₂) and one or more additionalfluoromonomers such as those selected from the group consisting offluorine-containing olefins, fluorine-containing ethers and mixturesthereof.

According to the present invention, fluorine-containing olefinscopolymerizable with vinylidene fluoride include, but are not limited tohexafluoropropylene (HFP), tetrafluoroethylene (TFE),1,2,3,3,3-pentafluoropropene (1-HPFP), chlorotrifluoroethylene (CTFE)and vinyl fluoride.

The fluorine-containing ethers that may be employed in thefluoroelastomers include, but are not limited to perfluoro(alkyl vinylethers), perfluoro(alkyl alkenyl ethers) and perfluoro(alkoxyalkenylethers).

Perfluoro(alkyl vinyl ethers) (PAVE) suitable for use as monomersinclude those of the formula

CF₂=CFO(R_(f′)O)_(n)(R_(f″)O)_(m)R_(f)  (I)

where R_(f)and R_(f)are different linear or branched perfluoroalkylenegroups of 2-6 carbon atoms, m and n are independently 0-10, and R_(f) isa perfluoroalkyl group of 1-6 carbon atoms.

A preferred class of perfluoro(alkyl vinyl ethers) includes compositionsof the formula

CF₂=CFO(CF₂CFXO)_(n)R_(f)  (II)

where X is F or CF₃, n is 0-5, and R_(f) is a perfluoroalkyl group of1-6 carbon atoms. A most preferred class of perfluoro(alkyl vinylethers) includes those ethers wherein n is 0 or 1 and R_(f) contains 1-3carbon atoms. Examples of such perfluorinated ethers includeperfluoro(methyl vinyl ether) (PMVE) and perfluoro(propyl vinyl ether)(PPVE). Other useful monomers include compounds of the formula

CF_(2=CFO[(CF) ₂)_(m)CF₂CFZO]_(n)R_(f)  (III)

where R_(f) is a perfluoroalkyl group having 1-6 carbon atoms, m=0 or 1,n=0-5, and Z=F or CF₃. Preferred members of this class are those inwhich R_(f) is C₃F₇, m=0, and n=1.

Additional perfluoro(alkyl vinyl ether) monomers include compounds ofthe formula

$\begin{matrix}{\text{CF}_{2} = {{\text{CFO}\lbrack {( {\text{CF}_{2}\text{CF}\{ \text{CF}_{3} \} \text{O}} )_{n}( {\text{CF}_{2}\text{CF}_{2}\text{CF}_{2}\text{O}} )_{m}( \text{CF}_{2} )_{p}} \rbrack}\text{C}_{x}\text{F}_{{2x} + 1}}} & ({IV})\end{matrix}$

where m and n independently=0-10, p=0-3, and x=1-5. Preferred members ofthis class include compounds where n=0-1, m=0-1, and x=1.

Other examples of useful perfluoro(alkyl vinyl ethers) include

CF₂=CFOCF₂CF(CF₃)O(CF₂O)_(m)C_(n)F_(2n+1)  (V)

where n=1-5, m=1-3, and where, preferably, n=1.

Perfluoro(alkyl alkenyl ethers) suitable for use as monomers includethose of the formula VI

R_(f)O(CF₂)_(n)CF=CF₂  (VI)

where R_(f) is a perfluorinated linear or branched aliphatic groupcontaining 1-20, preferably 1-10, and most preferably 1-4 carbon atomsand n is an integer between 1 and 4. Specific examples include, but arenot limited to perfluoro(propoxyallyl ether) andperfluoro(propoxybutenyl ether).

Perfluoro(alkoxy alkenyl ethers) differ from perfluoro(alkyl alkenylethers) in that R_(f) in formula VI contains at least one oxygen atom inthe aliphatic chain. A specific example includes, but is not limited toperfluoro(methoxyethoxyallyl ether).

If copolymerized units of a fluorine-containing ether are present in thefluoroelastomers of the invention, the ether unit content generallyranges from 25 to 75 weight percent, based on the total weight of thefluoroelastomer. If perfluoro(methyl vinyl) ether is used, then thefluoroelastomer preferably contains between 30 and 55 wt. %copolymerized PMVE units.

The fluoroelastomers of the present invention also contain cure sites ofbromine atoms, iodine atoms or both. The cure sites may be along thefluoroelastomer chain (i.e. due to copolymerized units of cure sitemonomer), at chain ends (i.e. due to polymerization in the presence of achain transfer agent), or both along fluoroelastomer chains and at chainends.

Brominated cure site monomers may contain other halogens, preferablyfluorine. Examples of brominated olefin cure site monomers areCF₂═CFOCF₂CF₂CF₂OCF₂CF₂Br; bromotrifluoroethylene;4-bromo-3,3,4,4-tetraflourobutene-1 (BTFB); and others such as vinylbromide, 1-bromo-2,2-difluoroethylene; perfluoroallyl bromide;4-bromo-1,1,2-trifluorobutene-1; 4-bromo-1,1,3,3,4,4,-hexafluorobutene;4-bromo-3-chloro-1,1,3,4,4-pentafluorobutene;6-bromo-5,5,6,6-tetrafluorohexene; 4-bromoperfluorobutene-1 and3,3-difluoroallyl bromide. Brominated vinyl ether cure site monomersuseful in the invention include 2-bromo-perfluoroethyl perfluorovinylether and fluorinated compounds of the class CF₂Br—R—O—CF═CF₂ (R_(f) isa perfluoroalkylene group), such as CF₂BrCF₂O—CF═CF₂, and fluorovinylethers of the class ROCF═CFBr or ROCBr═CF₂ (where R is a lower alkylgroup or fluoroalkyl group) such as CH₃OCF═CFBr or CF₃CH₂OCF═CFBr.

Suitable iodinated cure site monomers include iodinated olefins of theformula: CHR═CH-Z-CH₂CHR—I, wherein R is —H or —CH₃; Z is a C₁-C₁₈(per)fluoroalkylene radical, linear or branched, optionally containingone or more ether oxygen atoms, or a (per)fluoropolyoxyalkylene radicalas disclosed in U.S. Patent 5,674,959. Other examples of usefuliodinated cure site monomers are unsaturated ethers of the formula:I(CH₂CF₂CF₂)_(n)OCF═CF₂ and ICH₂CF₂O[CF(CF₃)CF₂O]_(n)CF═CF₂,and thelike, wherein n=1-3, such as disclosed in U.S. Pat. No. 5,717,036. Inaddition, suitable iodinated cure site monomers including iodoethylene,4-iodo-3,3,4,4-tetrafluorobutene-1 (ITFB); 3-chloro-4-iodo-3,4,4-trifluorobutene;2-iodo-1,1,2,2-tetrafluoro1-(vinyloxy)ethane;2-iodo-1(perfluorovinyloxy)-1,1,-2,2-tetrafluoroethylene;1,1,2,3,3,3-hexafluoro-2-iodo-1-(perfluorovinyloxy)propane; 2-iodoethylvinyl ether; 3,3,4,5,5,5-hexafluoro-4-iodopentene; andiodotrifluoroethylene are disclosed in U.S. Pat. No. 4,694,045. Allyliodide and 2-iodo-perfluoroethyl perfluorovinyl ether are also usefulcure site monomers.

Units of cure site monomer, when present in the fluoroelastomersemployed in this invention, are typically present at a level of 0.05-10wt. % (based on the total weight of fluoroelastomer), preferably 0.05-5wt. % and most preferably between 0.05 and 3 wt. %.

Additionally, iodine-containing endgroups, bromine-containing endgroupsor mixtures thereof may optionally be present at one or both of thefluoroelastomer polymer chain ends as a result of the use of chaintransfer or molecular weight regulating agents during preparation of thefluoroelastomers. The amount of chain transfer agent, when employed, iscalculated to result in an iodine or bromine level in thefluoroelastomer in the range of 0.005-5 wt. %, preferably 0.05-3 wt. %.

Examples of chain transfer agents include iodine-containing compoundsthat result in incorporation of bound iodine at one or both ends of thepolymer molecules. Methylene iodide; 1,4-diiodoperfluoro-n-butane; and1,6-diiodo-3,3,4,4,tetrafluorohexane are representative of such agents.Other iodinated chain transfer agents include1,3-diiodoperfluoropropane; 1,6-diiodoperfluorohexane;1,3-diiodo-2-chloroperfluoropropane;1,2-di(iododifluoromethyl)-perfluorocyclobutane;monoiodoperfluoroethane; monoiodoperfluorobutane;2-iodo-1-hydroperfluoroethane, etc. Also included are the cyano-iodinechain transfer agents disclosed European Patent 0868447A1. Particularlypreferred are diiodinated chain transfer agents.

Examples of brominated chain transfer agents include1-bromo-2-iodoperfluoroethane; 1-bromo-3-iodoperfluoropropane;1-iodo-2-bromo-1,1-difluoroethane and others such as disclosed in U.S.Pat. No. 5,151,492.

Two preferred fluoroelastomers that may be employed in this inventioncomprise copolymerized units of A) vinylidene fluoride,hexafluoropropylene and tetrafluoroethylene and B) vinylidene fluoride,perfluoro(methyl vinyl ether) and tetrafluoroethylene. Each of thelatter fluoroelastomers also contain cure sites of bromine atoms, iodineatoms, or both bromine and iodine atoms.

Organic peroxides suitable to cure the fluoroelastomer include, but arenot limited to 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane;1,1-bis(T-butylperoxy)cyclohexane; 2,2-bis(t-butylperoxy)octane;n-butyl-4,4bis(t-butylperoxy)valerate; 2,2-bis(t-butylperoxy)butane;2,5-dimethylhexane-2,5-dihydroxyperoxide; di-t-butyl peroxide;t-butylcumyl peroxide; dicumyl peroxide; alpha,alpha′-bis(t-butylperoxy-m-isopropyl)benzene;2,5-dimethyl-2,5-di(t-butylperoxy)hexane;2,5-dimethyl-2,5-di(t-butylperoxy)hexene-3; benzoyl peroxide,t-butylperoxybenzene; 2,5-dimethyl-2,5-di(benzoylperoxy)-hexane;t-butylperoxymaleic acid; and t-butylperoxyisopropylcarbonate. Preferredexamples of organic peroxides include2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, and alpha,alpha′-bis(t-butylperoxy-m-isopropyl)benzene. The amount compounded isgenerally in the range of 0.05-5 parts by weight, preferably in therange of 0.1-3 parts by weight per 100 parts by weight of thefluoroelastomer.

Multifunctional coagents that may be employed in the peroxide curing offluoroelastomer are polyfunctional unsaturated compounds such astriallyl cyanurate, trimethacryl isocyanurate, triallyl isocyanurate,trimethallyl isocyanurate, triacryl formal, triallyl trimellitate,N,N′-m-phenylene bismaleimide, diallyl phthalate,tetraallylterephthalamide, tri(diallylamine)-s-triazine, triallylphosphite, bis-olefins and N,N-diallylacrylamide. The amount compoundedis generally in the range of 0.1-10 parts by weight per 100 parts byweight of the fluoroelastomer.

The fluoroelastomer, organic peroxide, coagent, and any otheringredients are generally incorporated into curable compositions bymeans of an internal mixer or rubber mill. The resulting composition maythen be shaped (e.g. molded or extruded) and cured to form fluororubbercomponents. Curing typically takes place at about 150°-200° C. for 1 to60 minutes. Conventional rubber curing presses, molds, extruders, andthe like provided with suitable heating and curing means can be used.Also, for optimum physical properties and dimensional stability, it ispreferred to carry out a post curing operation wherein the molded orextruded fluororubber component is heated in an oven or the like for anadditional period of about 1-48 hours, typically from about 180°-275°C., generally in an air atmosphere.

EXAMPLES Test Methods Tensile Properties

The following physical property parameters were recorded prior toexposure to biodiesel fuel; test methods are in parentheses:

T_(b): tensile strength, MPa (ASTM D412-92)

E_(b): elongation at break, % (ASTM D412-92)

M100: modulus at 100% elongation, MPa (ASTM D412-92).

Hardness, Shore A (ASTM D412-92)

Volume Swell (%) after emersion in biodiesel was determined by ASTMD471-96 on standard ASTM D471 coupons. The coupons were prepared fromcured fluororubber slabs and immersed in biodiesel fuel in a sealed Parrvessel at the temperatures and for the times noted in the Examples. Fuelwas replaced with fresh fuel on a weekly basis.

The invention is further illustrated by, but is not limited to, thefollowing examples.

Fluoroelastomers employed in the examples are commercially availablefrom DuPont Performance Elastomers. FKM1 is Viton® A401C, FKM2 is Viton®GBL-600S. FKM3 is Viton® GF-600S. FKM4 is Viton® F605C. FKM5 is Viton®GFLT-600S. FKM6 is Viton® GLT-600S. A401C and F605C contain a bisphenolAF curing package. The other fluoroelastomers are cured with peroxide.

Examples 1-2 Comparative Examples A-E

Curable compositions for Examples 1-2and Comparative Examples A-B weremade by compounding the ingredients in an internal laboratory mixer andsheet off mill. Formulations are shown in Table I.

The compositions were molded into slabs and press cured at 177° C. for 5minutes, followed by post curing in air at 232° C. for 2 hours. Tensileproperties were measured according to the Test Methods and are alsoshown in Table I.

Coupons made from cured slabs were exposed to rapeseed oil methyl ester(B100 RME) and to a blend of 20 vol. % RME with petroleum diesel fuel(B20) for 1008 hours at 125° C. Results are shown in Table I.Fluororubber coupons that did not contain any inorganic acid acceptors(Examples 1 and 2) of the invention exhibited low (≦6%) volume swellwhereas coupons that did contain inorganic acid acceptors (ComparativeExamples A-E) show much higher volume swells, 14-99%.

TABLE I Comp. Comp. Comp. Comp. Comp. Ex. 1 Ex. 2 Ex. A Ex. B Ex. C Ex.D Ex. E Ingredient, phr¹ FKM1 0 0 100 0 0 0 0 FKM2 100 0 0 100 100 100 0FKM3 0 100 0 0 0 0 100 N990 30 30 30 30 30 30 30 Carbon Black Triallyl2.5 2.5 0 2.5 2.5 2.5 2.5 iso- cyanurate² Peroxide³ 1.5 1.5 0 1.5 1.51.5 1.5 MgO⁴ 0 0 3 0 3 0 0 Ca(OH)₂ 0 0 6 0 0 3 0 ZnO 0 0 0 3 0 0 3Tensile Properties: Hardness, 68 71 74 69 69 69 72 Shore A M100, 3.4 5.25.6 3.6 4.2 4.0 5.1 MPa Tb, MPa 17.9 18.1 13.9 18.3 17.8 19.3 18.4 Eb, %349 259 226 356 292 337 281 Volume Swell B20 6 5 56 18 14 39 15 Fuel, %B100 5 4 99 17 21 27 17 Fuel, % ¹parts by weight per hundred partsrubber (i.e. fluoroelastomer) ²Diak 7 (available from DuPont PerformanceElastomers ³Elastomag ® 170 (available from Rohm and Haas) ⁴Varox ®DBPH-50 (available from R.T. Vanderbilt)

Examples 3-4 Comparative Examples F-I

Cured slabs were prepared and cured as described in Example 1 from theformulations shown in Table 2 except that post cure was for 16 hours.Tensile properties are shown in Table 2. Coupons were exposed torapeseed oil methyl ester (B100 RME) and to blends of 5 vol. % RME and20 vol. % RME in petroleum diesel fuel (B5 and B20, respectively) for1008 hours at 125° C. The fuels contained 0.5 wt. % water. Results areshown in Table 2. Comparative examples (containing inorganic acidacceptors) all showed higher volume swell than Examples 3-4 (noinorganic acid acceptor), even in fuel containing only 5 vol. %biodiesel (B5).

TABLE II Comp. Come. Comp. Comp. Ex. 3 Ex. F Ex. G Ex. H Ex. I Ex. 4Ingredient, phr¹ FKM1 0 0 100 0 0 0 FKM2 100 100 0 100 0 0 FKM3 0 0 0 00 100 FKM4 0 0 0 0 100 0 N990 Carbon 30 30 30 30 30 30 Black Triallyl2.5 2.5 0 2.5 0 2.5 isocyanurate² Peroxide³ 1.5 1.5 0 1.5 0 1.5 MgO⁴ 0 03 0 3 0 Ca(OH)₂ 0 3 6 1.5 6 0 Tensile Properties: Hardness, 72 73 78 7279 76 Shore A M100, MPa 3.5 4.5 6.0 4.3 5.2 5.5 Tb, MPa 19.8 21.4 14.722.1 13.8 20 Eb, % 309 295 212 327 278 275 Volume Swell B100 Fuel, % 526 90 19 48 3 B20 Fuel, % 5 14 37 8 75 4 B5 Fuel, % 5 10 10 8 10 5

Examples 5-8

Cured slabs were prepared and cured as described in Example 1 from theformulations shown in Table 3 except that post cure was for 16 hours.Tensile properties are shown in Table 3. Coupons were exposed torapeseed oil methyl ester (B100 RME) for 3024 hours at 125° C. Resultsare shown in Table 3. Even after 3024 hours of exposure to biodieselfuel, the coupons of the invention (contained no inorganic acidacceptors) exhibited low volume swell.

TABLE 3 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ingredient, phr¹ FKM2 100 0 0 0 FKM3 0100 0 0 FKM5 0 0 100 0 FKM6 0 0 0 100 N990 Carbon 30 30 30 30 BlackTriallyl 2.5 2.5 2.5 2.5 isocyanurate² Peroxide³ 1.5 1.5 1.5 1.5 TensileProperties: Hardness, 71 76 72 68 Shore A M100, MPa 3.3 6.0 5.0 3.4 Tb,MPa 20.9 20.0 15.9 19.0 Eb, % 359 279 200 285 Volume Swell B100 Fuel, %5 4 5 6

1. In a fuel management system having at least one fluororubbercomponent in contact with biodiesel fuel, the improvement wherein saidfluororubber component comprises i) a peroxide cured fluoroelastomercomprising copolymerized units of vinylidene fluoride and at least oneother fluoromonomer, said fluoroelastomer having cure sites selectedfrom the group consisting of iodine and bromine atoms, and ii) 0 to 5000parts by weight of an inorganic acid acceptor per million partsfluoroelastomer.
 2. A fuel management system of claim 1 wherein saidbiodiesel fuel comprises a fatty acid alkyl ester of biological origin.3. A fuel management system of claim 2 wherein said fatty acid alkylester of biological origin is selected from the group consisting of rapeseed oil methyl ester, soybean oil methyl ester, and palm kernel oilmethyl ester.
 4. A fuel management system of claim 1 wherein saidbiodiesel fuel comprises a blend of a fatty acid alkyl ester ofbiological origin and petroleum diesel fuel.
 5. A fuel management systemof claim 1 wherein said fuel management system is in a motor vehicle. 6.A fuel management system of claim 1 wherein said fuel management systemis in a stationary diesel powered device.
 7. A fuel management system ofclaim 1 wherein said fuel management system is in a biodiesel supplysystem.
 8. A fuel management system of claim 1 wherein said fuelmanagement system is in a biodiesel manufacturing plant.
 9. A fuelmanagement system of claim 1 wherein said peroxide cured fluoroelastomercomprises copolymerized units of vinylidene fluoride,hexafluoropropylene and tetrafluoroethylene.
 10. A fuel managementsystem of claim 1 wherein said peroxide cured fluoroelastomer comprisescopolymerized units of vinylidene fluoride, perfluoro(methyl vinylether) and tetrafluoroethylene.
 11. A fuel management system of claim 1comprising 0 to 1000 parts by weight of an inorganic acid acceptor permillion parts fluoroelastomer.
 12. A fuel management system of claim 11comprising 0 to 500 parts by weight of an inorganic acid acceptor permillion parts fluoroelastomer.